Tutorial: Configure EC2 Fleet to use On-Demand Instances as the primary capacity

This page has not been translated into your language. Request translation

This tutorial uses a fictitious company called ABC Online to illustrate the process of requesting an EC2 Fleet with On-Demand as the primary capacity, and Spot capacity if available.

Objective

ABC Online, a restaurant delivery company, aims to provision Amazon EC2 capacity across EC2 instance types and purchasing options to achieve their desired scale, performance, and cost.

Plan

ABC Online requires a fixed capacity to handle peak periods, but would like to benefit from additional capacity at a lower cost. The company determines the following requirements for their EC2 Fleet:

• On-Demand Instance capacity – ABC Online requires 15 On-Demand Instances to ensure that they can accommodate traffic at peak periods.

• Spot Instance capacity – To enhance performance, but at a lower price, ABC Online plans to provision 5 Spot Instances.

Verify permissions

Before creating an EC2 Fleet, ABC Online verifies that it has an IAM role with the required permissions. For more information, see EC2 Fleet prerequisites.

Create a launch template

Next, ABC Online creates a launch template. The launch template ID is used in the following step. For more information, see Create an Amazon EC2 launch template.

Create the EC2 Fleet

ABC Online creates a file, config.json, with the following configuration for its EC2 Fleet. In the following example, replace the resource identifiers with your own resource identifiers.

{
    "LaunchTemplateConfigs": [
        {
            "LaunchTemplateSpecification": {
                "LaunchTemplateId": "lt-07b3bc7625cdab851",
                "Version": "2"
            }

        }
    ],
    "TargetCapacitySpecification": {
        "TotalTargetCapacity": 20,
        "OnDemandTargetCapacity":15,
        "DefaultTargetCapacityType": "spot"
    }
}

ABC Online creates the EC2 Fleet using the following create-fleet command.

aws ec2 create-fleet --cli-input-json file://config.json

For more information, see Create an EC2 Fleet.

Fulfillment

The allocation strategy determines that the On-Demand capacity is always fulfilled, while the balance of the target capacity is fulfilled as Spot if there is available capacity.